In recent years, gas turbines have been designed to operate at higher temperatures and with increased efficiency. This has led to a trend of increasing the length of the turbine blades (providing long blades). Such blades, while having a reduced vibration frequency due to the increased blade length, have an increased susceptibility to the occurrence to flutter and other unstable vibrations.
To combat this, tip shrouds have been disposed on the tips of blade bodies that constitute the turbine blades to increase the natural frequency and/or structural damping of the turbine blades, thus suppressing the occurrence of vibrations. Adjacent tip shrouds of such turbine blades abut one another to reduce leakage flow between blade tips. Vibrations are also dampened by the adjacent tip shrouds abutting one another. To prevent damage caused by heterogeneous contact and stress concentration at corner portions however, tip shrouds have been provided with a portion with a gap via which adjacent tip shrouds do not abut one another (see, for example, Patent Document 1).